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Articles 1 - 11 of 11

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman Apr 2017

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their ...


Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman Sep 2015

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O3(g) by catechol γO3 = (7.49 ± 0.35) × 10–6 occurs for ...


Aerosol Single Scattering Albedo Dependence On Biomass Combustion Efficiency: Laboratory And Field Studies, Shang Liu, Allison C. Aiken, Caleb Arata, Manvendra K. Dubey, C. Stockwell, Robert Yokelson, Elizabeth A. Stone, Thilina Jayarathne, Allen L. Robinson, Paul J. Demott, Sonia M. Kreidenweis Jan 2014

Aerosol Single Scattering Albedo Dependence On Biomass Combustion Efficiency: Laboratory And Field Studies, Shang Liu, Allison C. Aiken, Caleb Arata, Manvendra K. Dubey, C. Stockwell, Robert Yokelson, Elizabeth A. Stone, Thilina Jayarathne, Allen L. Robinson, Paul J. Demott, Sonia M. Kreidenweis

Chemistry and Biochemistry Faculty Publications

Single scattering albedo (ω) of fresh biomass burning (BB) aerosols produced from 92 controlled laboratory combustion experiments of 20 different woods and grasses was analyzed to determine the factors that control the variability in ω. Results show that ω varies strongly with fire-integrated modified combustion efficiency (MCEFI)—higher MCEFI results in lower ω values and greater spectral dependence of ω. A parameterization of ω as a function of MCEFI for fresh BB aerosols is derived from the laboratory data and is evaluated by field observations from two wildfires. The parameterization suggests that MCEFI explains 60% of ...


Measurements Of Gas‐Phase Inorganic And Organic Acids From Biomass Fires By Negative‐Ion Proton‐Transfer Chemical‐Ionization Mass Spectrometry, P. Veres, James M. Roberts, I. R. Burling, C. Warneke, Joost De Gouw, Robert J. Yokelson Dec 2010

Measurements Of Gas‐Phase Inorganic And Organic Acids From Biomass Fires By Negative‐Ion Proton‐Transfer Chemical‐Ionization Mass Spectrometry, P. Veres, James M. Roberts, I. R. Burling, C. Warneke, Joost De Gouw, Robert J. Yokelson

Chemistry and Biochemistry Faculty Publications

[1] Emissions from 34 laboratory biomass fires were investigated at the combustion facility of the U.S. Department of Agriculture Fire Sciences Laboratory in Missoula, Montana. Gas-phase organic and inorganic acids were quantified using negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), open-path Fourier transform infrared spectroscopy (OP-FTIR), and proton-transfer-reaction mass spectrometry (PTR-MS). NI-PT-CIMS is a novel technique that measures the mass-to-charge ratio (m/z) of ions generated from reactions of acetate (CH3C(O)O) ions with inorganic and organic acids. The emission ratios for various important reactive acids with respect to CO were determined. Emission ratios for isocyanic acid ...


An Analysis Of The Chemical Processes In The Smoke Plume From A Savanna Fire, Jorg Trentmann, Robert J. Yokelson, Peter V. Hobbs, Tanja Winterrath, Ted J. Christian, Meinrat O. Andreae, Sherri A. Mason Jun 2005

An Analysis Of The Chemical Processes In The Smoke Plume From A Savanna Fire, Jorg Trentmann, Robert J. Yokelson, Peter V. Hobbs, Tanja Winterrath, Ted J. Christian, Meinrat O. Andreae, Sherri A. Mason

Chemistry and Biochemistry Faculty Publications

[1] Photochemistry in young plumes from vegetation fires significantly transforms the initial fire emissions within the first hour after the emissions are injected into the atmosphere. Here we present an investigation of field measurements obtained in a smoke plume from a prescribed savanna fire during the SAFARI 2000 field experiment using a detailed photochemical box-dilution model. The dilution used in the model simulations was constrained by measurements of chemically passive tracers (e.g., CO) near and downwind of the fire. The emissions of the dominant carbonaceous compounds, including oxygenated ones, were taken into account. The field measurements revealed significant production ...


Comprehensive Laboratory Measurements Of Biomass-Burning Emissions: 2. First Intercomparison Of Open-Path Ftir, Ptr-Ms, And Gc-Ms/Fid/Ecd, Ted J. Christian, B. Kleiss, Robert J. Yokelson, R. Holzinger, P. J. Crutzen, Wein Min Hao, T. Shirai, Donald R. Blake Jan 2004

Comprehensive Laboratory Measurements Of Biomass-Burning Emissions: 2. First Intercomparison Of Open-Path Ftir, Ptr-Ms, And Gc-Ms/Fid/Ecd, Ted J. Christian, B. Kleiss, Robert J. Yokelson, R. Holzinger, P. J. Crutzen, Wein Min Hao, T. Shirai, Donald R. Blake

Chemistry and Biochemistry Faculty Publications

No abstract provided.


Comprehensive Laboratory Measurements Of Biomass-Burning Emissions: 1. Emissions From Indonesian, African, And Other Fuels, Ted J. Christian, B. Kleiss, Robert J. Yokelson, R. Holzinger, P. J. Crutzen, Wei Min Hao, B. H. Saharjo, Darold E. Ward Dec 2003

Comprehensive Laboratory Measurements Of Biomass-Burning Emissions: 1. Emissions From Indonesian, African, And Other Fuels, Ted J. Christian, B. Kleiss, Robert J. Yokelson, R. Holzinger, P. J. Crutzen, Wei Min Hao, B. H. Saharjo, Darold E. Ward

Chemistry and Biochemistry Faculty Publications

[1] Trace gas and particle emissions were measured from 47 laboratory fires burning 16 regionally to globally significant fuel types. Instrumentation included the following: open-path Fourier transform infrared spectroscopy; proton transfer reaction mass spectrometry; filter sampling with subsequent analysis of particles with diameter <2.5 μm for organic and elemental carbon and other elements; and canister sampling with subsequent analysis by gas chromatography (GC)/flame ionization detector, GC/electron capture detector, and GC/mass spectrometry. The emissions of 26 compounds are reported by fuel type. The results include the first detailed measurements of the emissions from Indonesian fuels. Carbon dioxide, CO, CH4, NH3, HCN, methanol, and acetic acid were the seven most abundant emissions (in order) from burning Indonesian peat. Acetol (hydroxyacetone) was a major, previously unobserved emission from burning rice straw (21–34 g/kg). The emission factors for our simulated African fires are consistent with field data for African fires for compounds measured in both ...


Distributions Of Trace Gases And Aerosols During The Dry Biomass Burning Season In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirschsetter Sep 2003

Distributions Of Trace Gases And Aerosols During The Dry Biomass Burning Season In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirschsetter

Chemistry and Biochemistry Faculty Publications

[1] Vertical profiles in the lower troposphere of temperature, relative humidity, sulfur dioxide (SO2), ozone (O3), condensation nuclei (CN), and carbon monoxide (CO), and horizontal distributions of twenty gaseous and particulate species, are presented for five regions of southern Africa during the dry biomass burning season of 2000. The regions are the semiarid savannas of northeast South Africa and northern Botswana, the savanna-forest mosaic of coastal Mozambique, the humid savanna of southern Zambia, and the desert of western Namibia. The highest average concentrations of carbon dioxide (CO2), CO, methane (CH4), O3, black particulate carbon, and ...


Trace Gas Measurements In Nascent, Aged, And Cloud-Processed Smoke From African Savanna Fires By Airborne Fourier Transform Infrared Spectroscopy (Aftir), Robert J. Yokelson, Issac T. Bertschi, Ted J. Christian, Peter V. Hobbs, Darold E. Ward, Wei Min Hao Jul 2003

Trace Gas Measurements In Nascent, Aged, And Cloud-Processed Smoke From African Savanna Fires By Airborne Fourier Transform Infrared Spectroscopy (Aftir), Robert J. Yokelson, Issac T. Bertschi, Ted J. Christian, Peter V. Hobbs, Darold E. Ward, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] We measured stable and reactive trace gases with an airborne Fourier transform infrared spectrometer (AFTIR) on the University of Washington Convair-580 research aircraft in August/September 2000 during the SAFARI 2000 dry season campaign in Southern Africa. The measurements included vertical profiles of CO2, CO, H2O, and CH4 up to 5.5 km on six occasions above instrumented ground sites and below the TERRA satellite and ER-2 high-flying research aircraft. We also measured the trace gas emissions from 10 African savanna fires. Five of these fires featured extensive ground-based fuel characterization, and two were in ...


Trace Gas And Particle Emissions From Fires In Large Diameter And Belowground Biomass Fuels, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, R. E. Babbitt, Ronald A. Susott, Jon G. Goode, Wei Min Hao Feb 2003

Trace Gas And Particle Emissions From Fires In Large Diameter And Belowground Biomass Fuels, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, R. E. Babbitt, Ronald A. Susott, Jon G. Goode, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] We adopt a working definition of residual smoldering combustion (RSC) as biomass combustion that produces emissions that are not lofted by strong fire-induced convection. RSC emissions can be produced for up to several weeks after the passage of a flame front and they are mostly unaffected by flames. Fuels prone to RSC include downed logs, duff, and organic soils. Limited observations in the tropics and the boreal forest suggest that RSC is a globally significant source of emissions to the troposphere. This source was previously uncharacterized. We measured the first emission factors (EF) for RSC in a series of ...


Trace Gas Emissions From The Production And Use Of Domestic Biofuels In Zambia Measured By Open-Path Fourier Transform Infrared Spectroscopy, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, Ted J. Christian, Wei Min Hao Feb 2003

Trace Gas Emissions From The Production And Use Of Domestic Biofuels In Zambia Measured By Open-Path Fourier Transform Infrared Spectroscopy, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, Ted J. Christian, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] Domestic biomass fuels (biofuels) were recently estimated to be the second largest source of carbon emissions from global biomass burning. Wood and charcoal provide approximately 90% and 10% of domestic energy in tropical Africa. In September 2000, we used open-path Fourier transform infrared (OP-FTIR) spectroscopy to quantify 18 of the most abundant trace gases emitted by wood and charcoal cooking fires and an earthen charcoal-making kiln in Zambia. These are the first in situ measurements of an extensive suite of trace gases emitted by tropical biofuel burning. We report emission ratios (ER) and emission factors (EF) for (in order ...